Anthropic cuts false positives in Claude’s biology filter

Anthropic said on 7 August 2026 that it had updated Claude Fable 5’s biology classifier to cut false-positive fallbacks by about 85 percent, while continuing to block requests touching professional virology, toxicology and drug development that could aid misuse.

Why it mattered It put a figure on what a safety filter cost ordinary users, such as people asking a model to read their lab results, and on how far a laboratory would loosen one.